BOSTON -- It's never been done before, but because childhood obesity has become so prevalent, there are now physical activity guidelines for toddlers.

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Video Report RESOURCES New Fitness Guidelines For Kids National Association for Sport and Physical Education

They were released Wednesday by the National Association for Sport and Physical Education.

"My kids go outside just about every day, and that's definitely important," parent Ian Karsarjian said.

"They ride their bikes outside, and as often as we can, we try to take them to the beach," parent Katee Pimental said.

But if you want smart, fit kids, they may need more.

"It's really key that kids have their heart beating -- that they're really running, even breaking a little bit of a sweat," fitness expert Julie Sweet said.

New guidelines call for a minimum of 30 minutes of daily structured physical play for toddlers and an hour for preschoolers.

"It doesn't have to be school-like. It doesn't have to be physical education, but it can be tossing the ball, badminton or showing children how to jump over a little rope -- little things, but little skill developers," Sweet said.

The guidelines also recommend an hour each day of unstructured or free play -- swinging, hanging out in the sand -- just not in front of the TV.

Experts said that the recommendations will do more than just prevent obesity.

"What we found is the more physically active kids are, the smarter they become," Sweet said.

They suggest you lead by example, and together, you'll enjoy fun.